(1) Field of the Invention
The present invention relates generally to conveyor systems and, more particularly, to a conveyor system having a cantilevered conveying belt including a cantilevered frame having at least one conveyor belt and a belt tension assembly.
(2) Description of the Prior Art
Conveyor systems such as those used for sorting packages often include an inductor for loading packages to a primary conveyor. U.S. Pat. Nos. 6,206,170 and 5,836,436, commonly owned by applicant, disclose examples of these conveyor systems and are incorporated herein in their entirety. For years, manufacturers of conveyor belt systems have attempted to create an inductor that is efficient, easy to repair, and easily adjustable with regard to the tension of the belts. These efforts have produced several inductor designs that are present in the industry, but none of these inductors offer the benefit of easy belt maintenance and repair.
For example, U.S. Pat. No. 5,083,657, issued to Kelsey, discloses an elaborate method of taking and folding a belt so that the belt makes a 45-degree turn around one pulley, then around another pulley and back out. One problem with this design is the speed at which the belt has to be run because of effect of the geometry. For example, when the horizontal portion of the belt runs at 6 feet per second, the angled portion of the belt is running at about 8 feet per second. Unfortunately, at about 9 feet per second, friction over pulleys can begin to cause the belt to heat up such that some belts may actually catch on fire.
Another example, U.S. Pat. No. 4,987,994 also to Kelsey, discloses drilling tiny holes in the end of the roller shafts and pressurizing the shafts to create an air bearing. One problem with this design is that it uses a large amount of air. In addition, if the air ever fails or the holes fill up with dust, this type of belt design may also cause the belt to inflame.
The most widely accepted designs include a plurality of strip belts rather than a single wide belt. However, a major problem is the weakness of the typical belt due to the splice therein to form the belt, which is usually the point of belt failure. While the belting industry has made improvements to splices, including pealing the surface of the belt before vulcanizing the belt back together, the splices still fail. When the splices fail, it is necessary to replace the belt, but existing conveying belt inductors in the sorters industry are difficult to change efficiently, causing increased costs of labor and downtime.
In addition, another major problem with belts is the fact that belts tend to stretch, thereby requiring adjustments to an inductor to maintain proper belt tension. A belt likes to be pulled and hates to be pushed. If a belt is being pulled, the live load actually creates more tension on the head pulley, which gives the inductor more driving force. When the belt is being pushed with a weight on it, the belt wants to buckle up, the tension actually loosens the tension and the driving force drop.
Thus, there remains a need for a new and improved sortation system having a primary conveyor and a cantilevered conveying belt which provides for quick change of belts while, at the same time, includes an automatic belt and tension assembly.